How to convert my game to a newer version?
Download the the most recent version of blender or the version of blender of your choice and simply run the file. Blender doesn't necessarily convert files except for the fact that you can import/export them. Right now i am running Blender v2.74.5 and if I want to use a 2.6x blender file I can the only thing that will probably be different is the interface differences. So you may not have any idea how/what they set the settings/options to.